The Brazilian forward, who joined Barca from Santos for 57million euros (£49.6m) in May, is the club's second most expensive signing of all time - after Zlatan Ibrahimovic - but he insists he is not at the Nou Camp to rival four-time Ballon d'Or winner Messi.
"My relationship with Messi is great," Neymar told reporters. "I'm sure that there'll be no problems. He is the leader, the best player in the world, and I am here to help him."
Neymar will make his home debut for Barca at the Nou Camp on Friday night against his former club Santos in the Gamper Trophy, Barca's traditional curtain raiser, and he admits he cannot wait for the occasion.
"It will be a special game against my old team-mates, who I have so much affection for, but I will defend the Barcelona shirt with pride," he continued in a press conference broadcast on Barca's official website.
"I always play with the same excitement, as if every game was the Champions League final. I am desperate to play in the Nou Camp."
Neymar made his first appearance in a Blaugrana shirt on Tuesday during a friendly with Lechia Gdansk in Poland, coming off the bench for the final 12 minutes of the 2-2 draw.
He was asked if he was surprised by the physical treatment the Polish side gave him.
"In Brazil it was even worse," he said. "I'm used to being fouled, it's part of football and it's not unusual."
Neymar joined up with the Barca squad for the first time on Monday after enjoying an extended break due to his participation in the Confederations Cup, and today he explained his first impressions of the club.
He added: "It's a new life for me, I'm delighted with my team-mates and the coach [Gerardo Martino] and I'm very happy to be here.
"I'm getting to know everyone and the atmosphere here is even better than I expected. It's a dream come true. I turn around and see players like Messi, Xavi [Hernandez], [Andres] Iniesta and [Carles] Puyol."
The player, who had his tonsils removed last month and admitted to losing three kilograms as a result, pledged to train even harder to get into perfect shape in time for the new season.
And he declared he would not be affected by the pressure to succeed at the club following his hotly-anticipated move.
"Pressure always exists but I will train so that I can fulfil everyone's expectations, and I hope to be able to have a great season," he added.